Magnetic toner and ink

Abstract

A magnetic toner or ink is used in an electrophotography. It comprises a resinous component and a magnetic having a spinel structure and having the formula ##EQU1## wherein M represents at least one of Mn, Ni, Co, Mg, Cu, Zn or Cd; and x is in a range of 0.5 to 1 and y is in a range of 0.1 to 0.571.

We claim: 
     
       1. A magnetic toner or ink which comprises a resinous component and a magnetic powder having the formula ##EQU4## wherein M represents at least one of Mn, Ni, Co, Mg, Cu, Zn or Cd; and x is in a range of 0.5 to 1 and y is in a range of 0.1 to less than 0.571. 
     
     
       2. A magnetic toner or ink according to claim 1 wherein said magnetic powder is incorporated at a ratio of 0.2 to 0.7 wt. parts to 1 wt. part of said resinous component. 
     
     
       3. A magnetic toner or ink according to claim 1 wherein said resinous component has a weight average molecular weight of 10 3  to 10 5 . 
     
     
       4. A magnetic toner or ink according to claim 1 wherein said magnetic powder has an average particle diameter of 0.2 to 0.8μ. 
     
     
       5. A magnetic toner or ink according to claim 1 wherein said resinous component is a homopolymer or copolymer of one or more monomers of styrene, vinylnaphthalene, vinyl esters, α-methylene aliphatic monocarboxylic acid esters, acrylonitrile, methacrylonitrile, acrylamide, vinyl ethers, vinyl ketones and N-vinyl compounds. 
     
     
       6. A magnetic toner or ink according to claim 1, wherein said magnetic powder is produced by reducing a corresponding ferrite powder or iron oxide powder in a reducing atmosphere at a temperature lower than 600° C. and combining said magnetic powder with a resinous component. 
     
     
       7. A magnetic toner or ink according to claim 1, wherein the value of x ranges from 0.5 to 0.98. 
     
     
       8. A magnetic toner or ink which comprises a resinous component and a magnetic powder having the formula ##EQU5## wherein M represents at least one of Mn, Ni, Co, Mg, Cu, Zn or Cd; and x is in a range of 0.5 to 1 and y is in a range of 0.3572 to 0.5540.